School bus crossing arms are designed to extend to a perpendicular position relative to a front bus bumper when a school bus stops to pick up or discharge passengers. In this perpendicular position, such a crossing arm will block arriving and departing passengers from crossing immediately in front of a school bus and below the bus driver's field of vision. U.S. Pat. No. 5,357,239, granted to me Oct. 18, 1994, shows such a crossing arm assembly, or "safety gate," pivotally mounted to a housing or mounting bracket. The mounting bracket includes a single flat back plate that fixedly mounts to the front bumper of a vehicle. The back plate includes holes or slots for receiving mounting bolts.
U.S. Pat. No. 3,153,398, granted Oct. 20, 1964 to George LaVeme Runkle and Gilbert S. Sheets, discloses a crossing arm assembly having a crossing arm shaped to fit in an elongated recess in the front bumper of a bus. The assembly also includes a rubber guard structure that has a hollow rectangular center portion that is cemented to the channel section and flange portions that seal off the bumper recess. A disadvantage of this crossing arm assembly is that the bumper must be modified to include an elongated recess.
U.S. Pat. No. 4,204,701 issued May 27, 1980 to Oltrogge (the Oltrogge patent) discloses a universal vehicle accessory attachment. The attachment includes an elongated, vertically-oriented mounting bracket or frame having a profile contoured to conform to the profile of the front surface of a bumper. However, the Oltrogge bracket is not configured to pivotally support a crossing arm beam or to significantly dampen vibrations transmitted between the vehicle bumper and the bracket.
U.S Pat. No. 5,564,359 issued Oct. 15, 1996 to Harder (the Harder patent) discloses a bumper-mounted guide that helps support the free end of a cantilevered, pivotally mounted crossing arm in a stowed position against a bus bumper. The guide includes a ramped guide surface positioned to receive and guide a slightly sagging crossing arm upward into the stowed position as the arm swings inward against the bumper.
A disadvantage of the Harder bumper-mounted guide design is that, when the crossing arm is in the stowed position, the ramped guide surface tends to urge the arm to slide outward and away from the bumper. In addition, the Harder guide and bumper bracket could not fit flush against the front surface of a bus bumper that has anything other than a flat profile. In addition, the Harder bumper bracket could not significantly dampen vibrations transmitted between the bus and the crossing arm assembly.
What is needed is a mounting arrangement for a crossing arm assembly that includes a mounting bracket that pivotally supports a cantilevered crossing arm and has a profile contoured to conform to the profile of a bumper.